[PATCH] D10356: scan-build: Add --analyzer-target option

[Honggyu Kim]

honggyu.kim added a comment.

Here's one more example.

  $ cat -n test.c
       1  int main(int argc, char** argv) {
       2    int a;
       3  #if __arm__
       4    int *p = 0;
       5    if (argc == 3)
       6      a = *p;
       7  #endif
       8    return a;
       9  }

If we cross compile this code with the following command:

  $ scan-build --use-cc=arm-linux-gnueabi-gcc arm-linux-gnueabi-gcc test.c
  scan-build: Using '/home/hong.gyu.kim/usr/bin/clang' for static analysis
  test.c:8:3: warning: Undefined or garbage value returned to caller
    return a;
    ^~~~~~~~
  1 warning generated.
  scan-build: 1 bug found.
  scan-build: Run 'scan-view /tmp/scan-build-2015-08-04-215933-29482-1' to examine bug reports.

I detected a bug but in #if __arm__ region, null point dereference can happen and there's no way to detect it with current scan-build implementation.
With --analyzer-target option, we can detect those target dependent code region properly as below:

  $ scan-build --analyzer-target=arm --use-cc=arm-linux-gnueabi-gcc arm-linux-gnueabi-gcc test.c
  scan-build: Using '/home/hong.gyu.kim/usr/bin/clang' for static analysis
  test.c:6:9: warning: Dereference of null pointer (loaded from variable 'p')
      a = *p;
          ^~
  test.c:8:3: warning: Undefined or garbage value returned to caller
    return a;
    ^~~~~~~~
  2 warnings generated.
  scan-build: 2 bugs found.
  scan-build: Run 'scan-view /tmp/scan-build-2015-08-04-215948-29652-1' to examine bug reports.

Now, "Dereference of null pointer" bug is found.


http://reviews.llvm.org/D10356